In beginning our study of the stars, let us put ourselves in the
position of the earliest observers. Let us first, like them, watch the
stars, and see how they appear from night to night.
We see, at the first glance, that the stars vary much in brightness. The
brightest ones--like Sirius, Capella, Arcturus, and Vega--are called
stars of the _first magnitude_. Those less brilliant, like the six
brightest of “the Dipper,” are said to be of the _second_ magnitude. All
the stars which can be seen with the unaided eye are thus divided into
six classes or _magnitudes_, according to their brightness.
CONSTELLATIONS. We also see that the stars are not uniformly distributed
over the sky. They seem to be arranged in groups, some of which take the
form of familiar objects. Every one knows the seven bright stars which
are called “the Dipper.” Another group resembles a _sickle_, another a
_cross_, and so on. All the stars in the heavens have been divided into
groups called constellations. Many of these were recognized and named at
a very early period.
We should become familiar with these constellations in order to study
the stars with any profit.
It is necessary, in the first place, to have some way of designating the
stars in each constellation. Many of the brighter stars have proper
names as Sirius, Arcturus, and Vega; but the great majority of them are
marked by the letters of the Greek alphabet. The brightest star in each
constellation is called α (alpha); the next brightest, β (beta); the
next, γ (gamma); and so on. The characters and names of the Greek
alphabet are as follows:
α, Alpha.
β, Beta.
γ, Gamma.
δ, Delta.
ε, Epsilon.
ζ, Zeta.
η, Eta.
θ, Theta.
ι, Iota.
κ, Kappa.
λ, Lambda.
μ, Mu.
ν, Nu.
ξ, Xi.
ο, Omicron.
π, Pi.
ρ, Rho.
σ, Sigma.
τ, Tau.
υ, Upsilon.
φ, Phi.
χ, Chi.
ψ, Psi.
ω, Omega.
These letters are followed by the Latin name of the constellation. Thus
Aldebaran is called α Tauri; Rigel, β Orionis; Sirius, α Canis Majoris.
If there are more stars in a constellation than can be named from the
Greek alphabet, the Roman alphabet is used in the same way; and when
both alphabets are exhausted, numbers are used.
CIRCUMPOLAR CONSTELLATIONS. One of the most important constellations,
and one easily recognized, is the Great Bear, or Ursa Major. It is
represented in Plate 1 on the Star Chart. It may be known by the seven
stars forming “the Dipper.” The Bear’s feet are marked by three pairs of
stars. These and the star in the nose can be readily found by means of
the lines drawn on the chart. It may be remarked here, that in all
cases the stars thus connected by lines are the leading stars of the
constellation. The stars α and β are called the Pointers. If a line be
drawn from β to α, and prolonged about five times the distance between
them, it will pass near an isolated star of the second magnitude known
as the Pole Star, or Polaris. This is the brightest star in the Little
Bear, or Ursa Minor (Plate 2). It is in the end of the handle of a
second “dipper,” smaller than the one in the Great Bear.
On the opposite side of the Pole Star from the Great Bear, and at about
the same distance, is another conspicuous constellation, called
Cassiopeia. Its five brightest stars form an irregular W, opening
towards the Pole Star (Plate 2).
About half-way between the two Dippers three stars of the third
magnitude will be seen, the only stars at all prominent in that
neighborhood. These belong to Draco, or the Dragon. The chart will show
that the other stars in the body of the monster form an irregular curve
around the Little Bear, while the head is marked by four stars arranged
in a trapezium. Two of these stars, β and γ, are quite bright. A little
less than half-way from Cassiopeia to the head of the Dragon is a
constellation known as Cepheus, five stars of which form an irregular K.
These five constellations never set in our latitude, and are called
circumpolar constellations.
CONSTELLATIONS VISIBLE IN SEPTEMBER. At this time the Great Bear will be
low down in the northwest, and the Dragon’s head nearly in the zenith.
If we draw a line from ζ to η of the Great Bear and prolong it, we shall
find that it will pass near a reddish star of the first magnitude. This
star is called Arcturus, or α Boötis, since it is the brightest star in
the constellation Boötes. Of its other conspicuous stars, four form a
cross. These and the remaining stars of the constellation can be readily
traced with the aid of Plate 3.
Near the Dragon’s head (Plate 4) may be seen a very bright star of the
first magnitude, shining with a pure white light. This star is Vega, or
α Lyræ.
If we draw a line from Arcturus to Vega (Plate 3), it will pass through
two constellations, the Crown, or Corona Borealis and Hercules. The
former is about one-third of the way from Arcturus to Vega, and consists
of a semicircle of six stars, the brightest of which is called Alphecca
or Gemma Coronæ,--“the gem of the crown.”
Hercules is about half-way between the Crown and Vega. This
constellation is marked by a trapezoid of stars of the third magnitude.
A star in one foot is near the Dragon’s head; there is also a star in
each shoulder, and one in the face.
Just across the Milky Way from Vega (Plate 5) is a star of the first
magnitude, called Altair, or α Aquilæ. This star marks the constellation
Aquila, or the Eagle, and may be recognized by a small star on each side
of it. These are the only important stars in this constellation.
In the Milky Way, between Altair and Cassiopeia (Plate 4), there is a
large constellation called Cygnus, or the Swan. Six of its stars form a
large cross, by which it will be readily known. α Cygni is often called
Deneb. It forms a large isosceles triangle with Altair and Vega.
Low down in the south, on the edge of the Milky Way (Plate 6), is a
constellation called Sagittarius, or the Archer. It may be known by
five stars forming an inverted dipper, often called “the Milk-dipper.”
The head is marked by a small triangle. The other stars, as seen by the
map, may be grouped so as to represent a bow and an arrow.
[Illustration: =I. STAR CHART OF THE PRINCIPAL CONSTELLATIONS=]
Low in the southwest is a bright red star called Antares, or α
Scorpionis.
The space between Sagittarius and Hercules and Scorpio is occupied by
the Serpent (Serpens) and the Serpent-bearer, or Ophiuchus (Plates 6 and
7). The head of the Serpent is near the Crown, and marked by a small
triangle. The head of Ophiuchus is close to the head of Hercules, and
may be known by a star of the second magnitude. Each shoulder is marked
by a pair of stars. His feet are near the Scorpion.
Nearly on a line with Arcturus and γ Ursæ Majoris (Plate 1), and rather
nearer the latter, is an isolated star of the third magnitude, called
Cor Caroli, or Charles’ Heart. This is the only prominent star in the
constellation of Canes Venatici, or the Hunting Dogs.
Cassiopeia is almost due east of the Pole Star. A line drawn from the
latter through β Cassiopeiæ and prolonged, passes through two stars of
the second and third magnitude. These, with two others farther to the
south, form a large square, called the Square of Pegasus. Three of
these, as seen by the chart (Plate 5), belong to the constellation
Pegasus, or the Winged Horse. α Pegasi is called Markab, and β is called
Algenib. The bright stars in the neck and nose can be found by the
chart.
[Illustration: =II. STAR CHART OF THE PRINCIPAL CONSTELLATIONS=]
The fourth star in the Square of Pegasus belongs (Plate 8) to the
constellation Andromeda. Nearly in a line with α Pegasi and this star
are two other bright stars belonging to Andromeda. The stars in her belt
may be found by the chart.
Following the direction of the line of stars in Andromeda just
mentioned, and bending a little towards the east, we come to Algol, or β
Persei, a remarkable variable star. This star may be readily recognized
from the fact, together with β and γ Andromeda and the four stars in the
Square of Pegasus, it forms a figure similar in outline to the Dipper in
Ursa Major, but much larger. If the handle of this great Dipper is made
straight instead of being bent, the star in the end of it is α Persei,
of the second magnitude. This star has one of the third magnitude on
each side of it. The other stars in Perseus may be found by the chart.
Just below θ in the head of Pegasus (Plate 9) are three stars of the
third and fourth magnitudes, forming a small arc. These mark the urn of
Aquarius, the Water-bearer. His body consists of a trapezium of four
stars of the third and fourth magnitudes. Small clusters of stars show
the course of the water flowing from his urn.
This stream enters the mouth of the Southern Fish, or Piscis Australis.
The only bright star in this constellation is Fomalhaut, which is of the
first magnitude, and at this time will be low down in the southeast.
To the south of Aquarius is Capricornus, or the Goat. He is marked by
three pairs of stars arranged in a triangle. One pair is in his head,
another in his tail, and the third in his knees.
Near Altair (Plate 5), and a little higher up, is a small diamond of
stars forming the Dolphin, or Delphinus.
A little to the west of the Dolphin, in the Milky Way, are four stars of
the fourth magnitude, which form the constellation Sagitta, or the
Arrow.
CONSTELLATIONS VISIBLE IN OCTOBER. If we look at the heavens at eight
o’clock on the 15th of October, we shall see that all the constellations
described above have shifted somewhat towards the west. Arcturus and
Antares have set. In the east, below Andromeda (Plate 10), we see a pair
of bright stars, which are the only conspicuous ones in the
constellation Aries, or the Ram.
About half-way between Aries and γ Andromedæ are three stars which form
a small triangle. This constellation is called Triangulum, or the
Triangle.
Between Aries and Pegasus is the constellation Pisces, or the Fishes.
The southernmost Fish may be recognized by a pentagon of small stars
lying below the back of Pegasus. There are no conspicuous stars in the
other Fish, which is directly below Andromeda.
CONSTELLATIONS VISIBLE IN NOVEMBER. At eight o’clock in the evening on
the 15th of November, we see at a glance that the constellations with
which we have become acquainted have moved yet farther to the westward.
Boötes, the Crown, Ophiuchus, and the Archer have set; Pegasus,
Cassiopeia, and Andromeda are overhead; while new constellations appear
in the east.
We notice at once (Plate 11) a very bright star in the northeast,
directly below Perseus. This is Capella, or α Aurigæ. There are five
other conspicuous stars in Auriga, or the Charioteer; and with Capella
they form an irregular pentagon.
Somewhat to the eastward (Plate 12), and a little lower down, is a very
bright red star. This is Aldebaran, or α Tauri. It is familiarly known
as the Bull’s eye. It will be noticed by the map that it is at one end
of a V which forms the face of the Bull. This group is known as the
Hyades. Somewhat above the Hyades is a smaller group, called the
Pleiades,--more commonly known as the Seven Stars, though few persons
can distinguish more than six. The bright star on the northern horn, or
β Tauri, is also in the foot of Auriga, and counts as γ of that
constellation.
All the space between Taurus and the Southern Fish, and below Aries and
Pisces (Plate 13), is occupied by Cetus, the Whale. The head is marked
by a triangle of rather conspicuous stars below Aries; the tail, by a
bright star of the second magnitude, which is now just about as far
above the horizon as Fomalhaut. On the body there are five stars,
forming a sort of sickle. About halfway between this sickle and the
triangle, in the head, is σ Ceti, which is also called Mira, or the
wonderful star.
CONSTELLATIONS VISIBLE IN DECEMBER. At eight o’clock in the evening in
the middle of December, we shall find that Hercules, Aquila, and
Capricornus have sunk below the horizon; while Vega and the Swan are on
the point of setting. The Great Bear is climbing up in the northeast. In
the east we behold by far the most brilliant group of constellations we
have yet seen. Capella and Aldebaran are now high up; and below the
former (Plate 12) is the splendid constellation of Orion. His belt, made
up of three stars in a straight line, will be recognized at once. Above
this, on one shoulder, is a star of the first magnitude, called
Betelgeuse, or α Orionis. About as far from the belt, on the other side,
is another star of the first magnitude, called Rigel. There are two
other fainter stars which form a large trapezium with Betelgeuse and
Rigel. The three small stars below the belt are upon the sword.
Below Orion (Plate 14) is a small trapezium of stars which are in the
constellation of Lepus, or the Hare. The head is marked by a small
triangle, as seen on the map.
To the north of Orion, and a little lower down (Plate 12), are two
bright stars near together, one of the first and the other of the second
magnitude. The latter is called Castor, and the former Pollux. These
stars are in the constellation of Gemini, or the Twins. A line of three
smaller stars just in the edge of the Milky Way marks the feet, and
another line of three the knees. Pollux forms a large triangle with
Capella and Betelgeuse.
CONSTELLATIONS VISIBLE IN JANUARY. At eight in the evening on the 15th
of January, Vega, Altair, the Dolphin, Aquarius, and Fomalhaut have
disappeared in the west; Deneb and the Square of Pegasus are near the
horizon; while Capella and Aldebaran are nearly overhead. Two stars of
exceeding brilliancy have come up in the west. The one farthest to the
south (Plate 14) is the brightest star in the whole heavens. It is
called Sirius, or the Dogstar; and is in the constellation of Canis
Major, or the Great Dog, which can be readily traced by the lines on the
map.
The other bright star is between Sirius and Pollux (Plate 12), and is
called Procyon. It is in Canis Minor, or the Little Dog. The only other
prominent star in this constellation is one of the third magnitude near
Procyon.
Procyon, Sirius, and Betelgeuse form a large equilateral triangle.
Orion and the group of constellations about it constitute by far the
most brilliant portion of the heavens, as seen in our latitude. There
are, in all, only about twenty stars of the first magnitude, and seven
of these are in this immediate vicinity.
CONSTELLATIONS VISIBLE IN FEBRUARY. If we look at the heavens at the
same time in the evening about the middle of February, we shall miss
Cygnus and Pegasus from the west. Auriga and Orion are nearly overhead.
Southeast of the Great Bear (Plate 15) is a red star of the first
magnitude, called Regulus, in the constellation of Leo, or the Lion.
There are five stars near Regulus, which together with it form a group
often called the Sickle. The star in the tail is Denebola, which makes a
right-angled triangle with two others near it.
[Illustration: =MAP SHOWING THE LOCATIONS OF NORTHERN CONSTELLATIONS=]
Between Leo and Gemini is the constellation Cancer, or the Crab. It
contains no bright stars, but a remarkable cluster of small stars called
Præsepe, or the Beehive.
Below Regulus (Plate 14) is a bright red star of the second magnitude,
called Cor Hydræ, or the Hydra’s Heart. The head of Hydra is marked by
five small stars. The coils of the monster can be traced by the map. A
portion of the constellation is on Plate 16.
CONSTELLATIONS VISIBLE IN MARCH. At the middle of March, the heavens
will have shifted round somewhat towards the west; but all the
conspicuous constellations of the preceding month are still visible,
while no new ones at all brilliant have come into view.
If we draw a line from the end of the Great Bear’s tail to Denebola, it
will pass through two constellations,--Canes Venatici, described above;
and Coma Berenices, or Berenice’s Hair, a large cluster of faint stars.
(Plate 15).
[Illustration: =MAP SHOWING THE LOCATIONS OF THE SOUTHERN CONSTELLATIONS
AND ALSO MANY REMARKABLE NEBULAR FORMS=
1. Double nebula in Gemini. 2. Double nebula of great brilliancy in Coma
Berenicis. 3. Small double nebula. 4. Curiously shaped nebula in
Ophiuchus. 5. Two nebulous spots in Canes Venatici. 6. Remarkable
veil-like nebula in Lyra. 7. Elliptical nebula in Perseus. 8. Nebulous
spot in Sagittarius, split into three pieces; a double star in center.
9. Large curiously-shaped nebula in Rober Caroli, filled with minute
stars. 10. Great nebula in Andromeda, visible to the eye. 11. Nebula in
Cetus. 12. Elongated nebula in Cygnus. 13. Brilliant round spots in
Sagittarius. 14. Round spots in Andromeda. 15-16. Spots in Orion and
Ursa Major. 17. Most remarkable of all nebula, in Orion. 18. Great oval
nebula in Vulpes, containing two darker nebulae. 19. Nebulous figure in
Canis Venaticus. 20. Nebular clouds in the Southern hemisphere.]
CONSTELLATIONS VISIBLE IN APRIL. At the middle of April, Aries and
Andromeda have set; Taurus, Orion and Canis Major are sinking towards
the west; the Great Bear and the Lion are overhead; Arcturus has risen
in the northeast (Plate 16); and some way to the south of this is seen a
star of the first magnitude, which forms a large triangle with Arcturus
and Denebola. It is called Spica Virginis, and is the chief star in the
constellation Virgo, or the Virgin. The stars on the breast and wings
can be found with the aid of the map.
South of Virgo is a trapezium of four stars, which are in the
constellation of Corvus, or the Crow.
CONSTELLATIONS VISIBLE IN MAY. At the middle of May, Taurus, Orion, and
Canis Major have set; Vega has just come up in the northeast; and
between Vega and Arcturus we again see Hercules and Corona. Below Spica
are two stars of the second magnitude, belonging to the constellation
Libra, or the Balance. Another star of the fourth magnitude forms a
triangle with these, and marks one pan of the balance. (Plate 7).
CONSTELLATIONS VISIBLE IN JUNE. In June we shall find that Canis Minor,
Perseus, Auriga, and Gemini have either set, or are on the point of
setting; Arcturus is overhead; Cygnus and Aquila are just rising.
Ophiuchus is well up; and low in the southeast we see again the red star
Antares, in the constellation Scorpio, or the Scorpion (Plate 6). There
is a star of the third magnitude on each side of Antares, and several
stars of the third and fourth magnitudes in the head and claws. The
configuration of these stars is much like a boy’s kite with a long tail.
Scorpio is a very brilliant constellation, and is seen to better
advantage in July and August.
CONSTELLATIONS VISIBLE IN JULY AND AUGUST. We have now described all the
important constellations visible in our latitude. Those which are seen
in July and August are mainly those described under the last two or
three months, and under September.
SOUTHERN CIRCUMPOLAR CONSTELLATIONS. There are a number of
constellations near the South Pole of the heavens which never rise in
our latitude, just as there are certain ones near the North Pole which
never set. These are called the southern circumpolar constellations.
=CONSTELLATIONS VISIBLE EACH MONTH=
The following table gives the constellations visible at eight
o’clock in the evening about the middle of each month. The stars
opposite the names of the constellations indicate those visible in
the month designated at the top.
+-------------------------------------------+-+-+-+-+-+-+-+-+-+-+-+-+
| |S|O|N|D|J|F|M|A|M|J|J|A|
| |e|c|o|e|a|e|a|p|a|u|u|u|
| NAME OF CONSTELLATION |p|t|v|c|n|b|r|r|y|n|l|g|
| |t|.|.|.|.|.|.|i| |e|y|.|
| |.| | | | | | |l| | | | |
+-------------------------------------------+-+-+-+-+-+-+-+-+-+-+-+-+
|=Ursa Major= (_er´sa mā´jor_). The Greater | | | | | | | | | | | | |
|Bear. |*|*|*|*|*|*|*|*|*|*|*|*|
|=Ursa Minor= (_er´sa mī´nor_). The Lesser | | | | | | | | | | | | |
|Bear. |*|*|*|*|*|*|*|*|*|*|*|*|
|=Draco= (_drak´ō_). Dragon. |*|*|*|*|*|*|*|*|*|*|*|*|
|=Cassiopeia= (_kas-si-o-pē´a_). Lady’s | | | | | | | | | | | | |
|Chair. |*|*|*|*|*|*|*|*|*|*|*|*|
|=Cepheus= (_sē´fe-us_). |*|*|*|*|*|*|*|*|*|*|*|*|
|=Bootes= (_bo-ō´tēz_). The Oxdriver or | | | | | | | | | | | | |
|Plowman. |*| | | | | | |*|*|*|*|*|
|=Corona Borealis= (_kō-rō´na bō-rē-ā´lis_).| | | | | | | | | | | | |
|The Northern Crown. |*|*| | | | | | |*|*|*|*|
|=Ophiuchus= (_of-i-u´kus_). The Serpent | | | | | | | | | | | | |
|Bearer. |*| | | | | | | | |*|*|*|
|=Sagittarius= (_saj-i-tā´ri-us_). The | | | | | | | | | | | | |
|Archer. |*| | | | | | | | | |*|*|
|=Hercules= (_her´ku-lēz_). |*|*| | | | | | |*|*|*|*|
|=Lyra= (_lī´ra_). The Lyre. |*|*|*| | | | | | |*|*|*|
|=Aquila= (_ak´wil-a_). |*|*|*| | | | | | | |*|*|
|=Delphinus= (_del´fin-us_). Dolphin. |*|*|*| | | | | | | |*|*|
|=Capricornus= (_kap-ri-kor´nus_). The Goat.|*|*|*| | | | | | | | |*|
|=Cygnus= (_sig´nus_). The Swan. |*|*|*|*| | | | | |*|*|*|
|=Sagitta= (_saj´it-ta_). The Arrow. |*|*|*| | | | | | | |*|*|
|=Aquarius= (_a-kwā´ri-us_). The Water- | | | | | | | | | | | | |
|bearer. |*|*|*|*| | | | | | | | |
|=Piscis Australis= (_pis´sis aw-strā´lis_).| | | | | | | | | | | | |
|The Southern Fish. |*|*|*|*| | | | | | | | |
|=Pegasus= (_peg´a-sus_). The Winged Horse. |*|*|*|*|*| | | | | | | |
|=Andromeda= (_an-drom´e-da_). |*|*|*|*|*|*|*| | | | | |
|=Perseus= (_per´sus_). |*|*|*|*|*|*|*|*| | | | |
|=Aries= (_a´ri-ēz_). Ram. | |*|*|*|*|*|*| | | | | |
|=Pisces= (_pis´sēz_). Fishes. | |*|*|*|*| | | | | | | |
|=Cetus= (_sē´tus_). The Whale. | | |*|*|*|*| | | | | | |
|=Triangulum= (_trī-ang´u-lum_). The | | | | | | | | | | | | |
|Triangle. | | |*|*|*|*|*| | | | | |
|=Auriga= (_aw-ri´ga_). The Waggoner or The | | | | | | | | | | | | |
|Charioteer. | | |*|*|*|*|*|*|*| | | |
|=Taurus= (_tau´rus_). The Bull. | | |*|*|*|*|*|*| | | | |
|=Lepus= (_lep´us_). The Hare. | | | |*|*|*|*| | | | | |
|=Orion= (_ō-ri´on_). Giant and Hunter. | | | |*|*|*|*|*| | | | |
|=Gemini= (_jem´i-ni_). The Twins. | | | |*|*|*|*|*|*| | | |
|=Canis Major= (_kā´nis mā´jor_). The Great | | | | | | | | | | | | |
|Dog. | | | | |*|*|*|*| | | | |
|=Canis Minor= (_kā´nis mī´nor_). The Little| | | | | | | | | | | | |
|Dog. | | | | |*|*|*|*|*| | | |
|=Cancer= (_kan´ser_). The Crab. | | | | | |*|*|*|*|*| | |
|=Hydra= (_hī´dra_). The Snake. | | | | | |*|*|*|*|*| | |
|=Leo= (_lē´ō_). The Lion. | | | | | |*|*|*|*|*|*| |
|=Coma Berenices= (_kō´ma ber-e-nī´sēz_). | | | | | | | | | | | | |
|Hair of Berenice. | | | | | | |*|*|*|*|*|*|
|=Canes Venatici= (_ka´nēz vē-nā´ti-si_). | | | | | | | | | | | | |
|The Hunter’s Dogs. | | | | | | |*|*|*|*|*|*|
|=Virgo= (_ver´gō_). The Virgin. | | | | | | | |*|*|*|*|*|
|=Corvus= (_kor´vus_). The crow. | | | | | | | |*|*|*|*| |
|=Libra= (_li´bra_). Balance. | | | | | | | |*|*|*|*| |
|=Scorpio= (_skor´pi-ō_). The Scorpion. | | | | | | | | | |*|*|*|
+-------------------------------------------+-+-+-+-+-+-+-+-+-+-+-+-+